Weeds under the canopies of tree species submitted to different planting densities and intercropping Plantas daninhas sob copas de espécies arbóreas submetidas a consórcios e densidades de plantio diferentes

Assessing the growth and floristic composition of species that grow under the canopy of trees is important for weed control (WC). The objective of this study was to assess two experiments (E1 and E2), when the trees were two years and one year of age, respectively. In E1, sabiá (S) and gliricidia (G) were submitted to planting densities from 400 to 1.200 plants ha-1. In E2, growing systems consisting of S, G, and neem (N) combinations were compared: SSS, GGG, NNN, GSG, NSN, SGS, NGN, SNS, and GNG (each letter represents a row of plants). A random block design was adopted, with three (E1) and four (E2) replicates. In E1, treatments were arranged as split-plots (species in plots). In E2, the degrees of freedom for treatments (8) were partitioned into growing systems (treatments that involved the same species) and between growing system groups (2). Twenty-one weed species were found in E1. Gliricidia attained greater plant height than sabiá, but these species did not differ in canopy diameter, number of weed species per plot, and weed green and dry biomass of the shoot. Higher planting densities resulted in the reduction of all those traits. Twenty-six weed species were found in E2. Growing systems that included gliricidia showed canopies with greater diameters than growing systems that included neem. There were no differences between growing systems for number of weed species per plot and for weed green and dry biomass of the shoot. Avalia es do crescimento e da composi o florística de espécies que vegetam sob a copa das árvores s o importantes no controle de plantas daninhas (PD). O objetivo deste trabalho foi realizar essas avalia es em dois experimentos (E1 e E2), quando as árvores tinham idades de dois anos e um ano, respectivamente. Em E1, sabiá (S) e gliricídia (G) foram submetidas a densidades de plantio de 400 a 1.200 plantas ha-1. Em E2, foram comparados sistemas de cultivo de S, G e nim (N): SSS, GGG, NNN, GSG, NSN, SGS, NGN, SNS e GNG (cada letra representa uma fileira de plantas). Utilizou-se o delineamento de blocos ao acaso com três (E1) e quatro repeti es (E2). Os tratamentos foram dispostos em parcelas subdivididas em E1 (espécies nas parcelas). No E2, os graus de liberdade de tratamentos (8) foram desdobrados em sistemas de cultivo (tratamentos que envolveram uma mesma espécie) e entre grupos de sistemas de cultivo (2). No E1 ocorreram 21 espécies de PD. A gliricídia apresentou maior altura da planta do que a sabiá, porém as duas espécies n o diferiram quanto a diametro da copa, número de espécies de PD por parcela e biomassas fresca